Vane anemometers

ABSTRACT

A vane anemometer of high sensitivity is comprised of an openended frame with an integral central housing at the front thereof for mounting a clockwork register mechanism. An impeller shaft mounting a plurality of radial vanes operates within the frame between the housing and a detachable spider mount at the rear of the frame. Aligned miniature ball-bearing assemblies at the hub of the spider and in the clockwork register mechanism support the opposite needle ends of the impeller shaft so that air currents of low velocities actuate the impeller shaft to register the movements of the latter, which are indicated on the face of the register.

[45] July 16, 1974 United States Patent [191 Rudow et al.

[ 1 VANE ANEMOMETERS [75] Inventors: Maurice G. Rudow; Warren D. Prima'y Goldstein Klawans, both of Baltimore, Md Attorney, Agent, or Firm-Samuel Lebowitz [73] Assignee: Davis Instrument Manufacturing ABSTRACT Baltlmore A vane anemometer of high sensitivity is comprised of an open-ended frame with an integral central housing at the front thereof for mounting a clockwork register 3 7 9 1 8%.! 2 a an F3 0 N L P p FA NH 22 mechanism. An impeller shaft mounting a plurality of radial vanes operates within the frame between the 52 US. Cl. 73/231 R, 73/189 housing and a detachable spider mum at the r f the frame. Aligned miniature ball-bearing assemblies at the hub of the spider and in the clockwork register Int. GOlf 1/02 mechanism support the opposite needle ends of the impeller shaft so that air currents of low velocities ac- [56] References Cited S T m m N m m E u n T m m A mnm P mmm S mmm E m d T mam A m T u SDOP D mma H999 NHHH 74 094 546 076 564 ,9 2

f. 0.5 g t nr 6 m 6 f. O0 6 m m m u c .W m F tn g m o .m W mw a M r. an 2 an a h. 5 se m .1 a a h C eC P 3 .mw r m t 6h Met Uhe ttt 9 9 232 222 333 777 VANE ANEMOMETERS This invention relates to vane anemometers adapted to measure air-flow, and particularly to portable instru' ments designed for the accurate measurement of low gas velocities in both confined or open spaces, such as mines, ducts, flues, fans, shafts, and the like.

It is the object of the present invention to provide an anemometer which is both rugged and accurate, and which is capable of economical assembly and servicing, so that the unit may function reliably over long periods of time.

The invention proceeds upon the principle of providing miniaturized ball-bearing assemblies for the needle ends of the main rotary shaft of the anemometer which permits the rotation thereof with minimal friction, even with some tolerable misalignment of the ends of the shaft, so that weak air currents are capable of effecting the movement of the radial vanes mounted on the shaft, so that the register mechanism may indicate low air velocities of the order of thirty feet per minute.

Other objects and purposes will appear from the detailed description of the invention following hereinafter, taken in conjunction with the accompanying drawings, wherein FIG. 1 is a front elevation of a preferred embodiment of the vane anemometer in accordance with the invention; and

FIG. 2 is a vertical sectional view along line 2-2 of FIG. 1.

Vane anemometers of the type contemplated by the instant invention have been known for many decades, as exemplified by those described in the US. Pats. to Davis, Nos. 1,050,350 and 1,905,444, and in US. Pat. No. 943,962, Dec. 21, 1909. However, heretofore none has had the sensitivity which characterizes the instrument in accordance with the present invention.

The instrumentis primarily comprised of a cylindrical open-ended frame F trough which may course the air currents which react upon the radial vanes V of the impeller mounted within the frame, and the velocities of which are recorded by a clockwork counting register M, mounted at the center of the frame.

The frame F may be die-cast of metal or other material, with an integral housing H at the front portion of the frame which is supported by a plurality of integral v radial arms 1 extending between the housing and the frame. The front end 2 of the housing is open for the reception of a clockwork counting register mechanism M which is supported and inserted into the housing by a knurled ring on the front of which may be provided a protective crystal 11.

The frame is provided with supporting feet 5,5 at the bottom thereof for positioning on any suitable support, and is also provided at the top thereof with an apertured lug 6 through which is passed a holding ring 7 to facilitate the portability of the instrument from place to place.

The counting register mechanism is provided with a zero-setting lever 8 and a disconnect lever 9 for uncoupling the register mechanism from the rotary impeller, as is well known in the art.

The face plate P of the register mechanism is provided with a main pointer 13 sweeping over a large circular dial l4 registering 100 units. The accumulated reading of the revolutions of the rotary shaft of the anemometer is registered on the dial l3 and secondary dials 15 and 17. The pointer 16 sweeping dial 15 makes a complete revolution for every ten revolutions of the pointer 13. Additionally, the pointer 18 sweeping the secondary dial l7 makes one revolution for every 10 revolutions of pointer 16, all as well known in the art.

The main rotary shaft 50 of the anemometer is provided with cylindrical needle ends 51 and 52 having a diameter of the order of 0.0245 inch. These needle ends are seated in the inner races of miniaturized ballbearings, which have a diameter .of 0.025 inch with conventional manufacturing tolerances. One of the ball. bearing assemblies 30 is seated within a cylindrical bore 29 provided within plates 28 of the rear portion of the cage of the counting register mechanism M. The outer race 31 of the ball-bearing assembly 30 is seated snugly within the bore 29, and the inner race 32 not only confines the ball-bearing cage 33 which is fitted with a dust shield 34 to maintain the bearings clean, but also provides a socket for the needle end 51 of the main rotary shaft.

The support of the opposite end of the main rotary shaft is afforded by a spider mounting 20 having a plurality of arms 21 extending radially from a central hub 22. The outer extremities of the arms are provided with threaded bores for the reception of threaded bolts 45 which extend from the outer periphery of the frame into the threaded bores of the arms in order to detachably interconnect the spider mount with the frame F. The radial arms 21 at the rear of the frame may be coincident with or angularly displaced relative to the integral arms 1 at the front of the frame.

The central hub 22 of the spider mount 20 is provided with a threaded bore 23 for receiving a threaded bolt 25 having a kerf 27 or other tool-engaging expedient at the rear end thereof and a cylindrical socket 26 at the opposite end thereof. A miniaturized ballbearing assembly 40, similar to the ball-bearing assembly 30, is adapted to be pressed into the cylindrical socket 26 at the external surface of the outer raceway 41. The inner raceway 42, which confines the cage of ball bearings, also seats the needle end 52 of the shaft 50.

The provision of the miniature ball-bearing assemblies at the opposite ends of the main rotary shaft, permits free substantially frictionless movement of the shaft despite some misalignment of the latter, since the ball bearings permit such movement whether the needle ends 51 and 52 are in perfect coaxial alignment with the longitudinal axis of the shaft 50 or are misaligned in some slight degree. The shaft rotates without binding in consequence of the movement permitted the inner race by the ball bearings.

A plurality of longitudinal splines 53 are provided at the end of the shaft 50 adjacent the needle end 51 to constitute a pinion which is maintained in engagement with the gear wheel 55 which may be considered the input wheel of the register mechanism, the movement of which is transmitted therefrom through the several gears of the clockwork mechanism to the several pointers 13, 16 and 18 which sweep the face plate P of the register.

The vanes V of the impeller are mounted on stems which are clamped to the rotary shaft 50 by means of fastening flanges 61 and 62. The latter is pressed onto the shaft beyond the splines 53 and the inner face is provided with radial grooves for seating the cylindrical stems 60. The inner face of the circular flange 61 is likewise provided with radial grooves which embrace the stems by clamping the flange 61 against flange 62 by means of bolts 63 which are threaded into aligned threaded openings in flanges 61 and 62 between the semi-cylindrical grooves in the latter adjacent to the peripheries thereof. The vanes are so designed that they occupy nearly all of the space between the inner wall of the frame and the outer wall of the register mechanism housing to attain maximum efficiency for the unit.

The ball-bearing mounting for the ball bearing assembly 40 is capable of ready interchangeability in the hub 22 of the spider mount in view of the integrated unit of the assembly 40 within threaded bolt 25. Following the insertion of the latter, it may be fixed more securely by the provision of a set screw 67 which may be operated from the exterior of the hub to press the inner end of the set screw against the periphery of the mounting bolt 25.

The ready interchangeability of the parts renders servicing of the units both easy and economical.

We claim:

l. A vane anemometer comprising a. a cylindrical open-ended frame,

b. a housing at the front part of said frame supported by a plurality of radial arms extending between said housing and frame,

c. a clockwork counting register mechanism mounted within said housing and provided with a stop lever and zero-reset lever extending radially therefrom,

d. said housing having a large opening at the front thereof for receiving the counting register mechanism with the dials and pointers on a face-plate facing outwardly at the front thereof, and a small aperture in the rear wall of said housing adjacent to the rearward portion of said counting register mechanism,

e. said counting register mechanism including a gear wheel transmission extending from an input wheel adjacent to said aperture to said plurality of pointers sweeping the dials 0n the face-plate of said counting register mechanism,

f. a rotary shaft comprising a main cylindrical portion and coaxial cylindrical needle ends of reduced diameter at the opposite ends of said main portion,

g. a pair of miniaturized ball-bearing assemblies for supporting said needle ends so that said shaft rotates with minimal frictional resistance,

h. one of said ball-bearing assemblies being seated in a circular opening in the rearward portion of said counting register mechanism, with the inner race of the assembly positioned to receive one of said needle ends,

. a multi-armed spider mount with the radial arms thereof detachably mounted within said frame adjacent to the rear portion thereof and provided with a threaded bore at the center of said spider,

. a threaded bolt engageable within said bore having tool-engageable means at the outer end thereof and a cylindrical recess at the inner end thereof,

k. the second one of said ball-bearing assemblies seated within said recess with the inner race positioned to receive the second one of said needle ends,

l. a plurality of longitudinal splines in the main cylindrical portion of said rotary shaft adjacent to said first needle end'and in the field of operation of said input wheel adapted to function as a pinion in engagement with said wheel upon the rotation of said rotary shaft, and

m. a plurality of radially extending vanes mounted on the main cylindrical portion of said rotary shaft between said splines and the second needle end.

2. A device as set forth in claim 1, wherein the toolengageable means in said threaded bolt is a kerf adapted to be operation by a screwdriver.

3.'A device as set forth in claim 1, wherein the longitudinal splines in the main cylindrical portion of the rotary shaft are at the end of said portion adjacent to the first needle end. 

1. A vane anemometer comprising a. a cylindrical open-ended frame, b. a housing at the front part of said frame supported by a plurality of radial arms extending between said housing and frame, c. a clockwork counting register mechanism mounted within said housing and provided with a stop lever and zero-reset lever extending radially therefrom, d. said housing having a large opening at the front thereof for receiving the counting register mechanism with the dials and pointers on a face-plate facing outwardly at the front thereof, and a small aperture in the rear wall of said housing adjacent to the rearward portion of said counting register mechanism, e. said counting register mechanism including a gear wheel transmission extending from an input wheel adjacent to said aperture to said plurality of pointers sweeping the dials on the face-plate of said counting register mechanism, f. a rotary shaft comprising a main cylindrical portion and coaxial cylindrical needle ends of reduced diameter at the opposite ends of said main portion, g. a pair of miniaturized ball-bearing assemblies for supporting said needle ends so that said shaft rotates with minimal frictional resistance, h. one of said ball-bearing assemblies being seated in a circular opening in the rearward portion of said counting register mechanism, with the inner race of the assembly positioned to receive one of said needle ends, i. a multi-armed spider mount with the radial arms thereof detachably mounted within said frame adjacent to the rear portion thereof and provided with a threaded bore at the center of said spider, j. a threaded bolt engageable within said bore having toolengageable means at the outer end thereof and a cylindrical recess at the inner end thereof, k. the second one of said ball-bearing assemblies seated within said recess with the inner race positioned to receive the second one of said needle ends, l. a plurality of longitudinal splines in the main cylindrical portion of said rotary shaft adjacent to said first needle end and in the field of operation of said input wheel adapted to function as a pinion in engagement with said wheel upon the rotation of said rotary shaft, and m. a plurality of radially extending vanes mounted on the main cylindrical portion of said rotary shaft between said splines and the second needle end.
 2. A device as set forth in claim 1, wherein the tool-engageable means in said threaded bolt is a kerf adapted to be operation by a screwdriver.
 3. A device as set forth in claim 1, wherein the longitudinal splines in the main cylindrical portion of the rotary shaft are at the end of said portion adjacent to the first needle end. 